Re: M421VT LED Screen Color Distortion
Hello NTT,
I finally got around to attempting the BGA on the VIZIO main board...Unfortunately I failed. I followed your instructions (which are very good) but,,the problem came at the point of the last hi temp application (217c).
my assistant had the temp probe on the chip monitoring the temp and when the probe was removed it lifted the chip from the board and little balls went rolling,,lol..
So,,,I'm trying to find a TXACB5K05302 main board,,they are hard to find right now,,got a request in at SJ......
dfang
Member
Last Activity: 06-21-2016, 08:15 AM
Joined: 02-10-2013
Location: Micco Florida
-
Re: M421VT LED Screen Color Distortion
Ok NTT,,got some flux,,,what is your recommended procedure for doing the Ball Grind flow with the equipment I have ? Do I need to remove heat sink ? Do I need to protect other components with aluminum foil ? I have a thermometer with probe..Leave a comment:
-
Re: M421VT LED Screen Color Distortion
Grrrr! Well,,I am a expert at that..
...
Leave a comment:
-
Re: M421VT LED Screen Color Distortion
Does heat shield need to come off ? Please say NO.....Leave a comment:
-
Re: M421VT LED Screen Color Distortion
Ah Ha...well,,I'm a gambler,,so,,no problem..What exactly does BGA look like on main board ? Btw I have reflowed computer Nvidia graphics cards before with mixed results.....Leave a comment:
-
Re: M421VT LED Screen Color Distortion
Ok,,I'll have to get some next week..
Thanks NTT......Leave a comment:
-
Re: M421VT LED Screen Color Distortion
I've got paste tinning flux and heat gun.....Leave a comment:
-
Re: M421VT LED Screen Color Distortion
Well,,,we are not back to original fault because something happened between then and now..After my heat/cool procedure I lost the display all together..
With the main board connected,,the only voltage is the two 5.2vdc pins...no 24v and no 12v at PS connector..
Btw,,I reinstalled the shield on the main.....Leave a comment:
-
Re: M421VT LED Screen Color Distortion
Ok,,,disconnected ON/OFF jumper but left 5.2v jumped to PS_ON at main board connector,,,,no voltage on 24v pins at PS connector and no backlights.....Leave a comment:
-
Re: M421VT LED Screen Color Distortion
I have jumper for PS_ON and ON-OFF.....Leave a comment:
-
Re: M421VT LED Screen Color Distortion
Any more suggestions ? I hate to give up,,but,,looks like the cost of boards to try (if they can be found) are not worth the TV..I do appreciate the help and did learn some things for future repair attempts..Leave a comment:
-
Re: M421VT LED Screen Color Distortion
I'm back to square one,,,I found a bad connection with my resistor jumpers at Main board connector..
Now with forced PS operation I get 14.47v at 24v pins...backlights blink off and on rapidly when tv is plugged in..Used DVA adapter on my Fluke to capture the max voltage..Something is shutting down PS...Don't know what else to try ..Leave a comment:
-
Re: M421VT LED Screen Color Distortion
Humm...disconnected backlights from PSU and forcing it on I get nothing on 24V lines... I reconnected backlights and now not even varying voltage on 24v pins on PS connector when plugged in..
I'm doing harm to this tv.....
Leave a comment:
-
Re: M421VT LED Screen Color Distortion
Ok,,first off I guess my Fluke is autoranging...I did a test with jumper resistors and realized that when the set is first plugged in the VIZIO logo will blink bright white 35 times then stop,,it is the back lights blinking...With meter on one of the 24v lines at the PS,,I see the voltage as high as 11.72vdc,,but it happens so fast the meter can't read the full correct voltage..After the 35 blinks and press TV power on backlight gives a very quick flash and that is it until you unplug/plug in and it starts the dance again..So the PS must be...Leave a comment:
-
Re: M421VT LED Screen Color Distortion
I've got Fluke ET-23 a old one,,but,,it works fine...It's manual ranging..I tried all ranges ..Could the PS power on voltage need to be greater than 4.24 volts ? I looked on the net for a main board and couldn't find one ,,,every one is out of stock...Must be a run on these babies..Leave a comment:
-
Re: M421VT LED Screen Color Distortion
Ok so I jumped 5v to on/off pin and 5v to PS_ON as well ..the results are still no 24v,,, of coarse no LED back lights...This is what I've got for voltages at PS now..
ON-OFF=4.24vdc
DIM=3.28vdc
12v=2.52vdc
12v=2.53vdc
GND=0vdc
GND=0vdc
GND=0vdc
24v=0vdc
24v=0vdc
PS_ON=4.24vdc
5.2v=5.14vdc
5.2v=5.14vdc
ACD=0vdcLeave a comment:
-
Re: M421VT LED Screen Color Distortion
Will attack it tomorrow,,I'm learning a lot...
Thanks for the help from you all......Leave a comment:
-
Re: M421VT LED Screen Color Distortion
Force PSU on again ? You mean jump with resistor at main board connector as before ? Use another resistor from where to ON/OFF pin ? STBY 5.2v ?...Leave a comment:
-
Re: M421VT LED Screen Color Distortion
Ok,,with resistor jumped at main board connector,,PS Voltages are now:
ON-OFF=0vdc
DIM=3.28vdc
12v=2.52vdc
12v=2.53vdc
GND=0vdc
GND=0vdc
GND=0vdc
24v=0vdc
24v=0vdc
5.2v=5.14vdc
5.2v=5.14vdc
ACD=0vdc
I would like to have a known good main to try......Leave a comment:
-
Re: M421VT LED Screen Color Distortion
Ok,,got shield back off,,man I should put a zipper on this shield..
I don't see anything obvious but got to thinking,,,could have put too much heat on the board with heat gun and unsoldered some electronic parts......Leave a comment:
No activity results to display
Leave a comment: